The Obama administration has directed the military to not allow personnel to say “Christmas”, in spite of the holiday’s status as a federally-recognized holiday.
The reason given by armed forces officials is that not everyone celebrates Christmas and that out of respect for them, military members should refer to Christmas celebrations simply as “holiday”-themed festivities.
This prohibition comes in the context of a wider push for political correctness in society in general and the military in particular, as evidenced by the recent reprimanding of Navy Chaplain Wes Modder for simply discussing religion, as chaplains are wont to do, with military personnel.
See how servicemen have reacted to not being allowed to say Christmas at the link below:

Strong message to follow.
The Potus is a Pos.
Impeach and exile for treason
Is there no end to the audacity of this evil man?
Not true!
Then he shall not observe Ramadan!
This story is a blatant lie. Propaganda (left or right) especially when it pulls in the military is disgraceful.
It’s unfortunate how much c**p this “man” has done to hurt Americans, and yet some Americans still believe he wants to better America.
He deserves zero respect from Americans.
Freedom of speech. Say any thing you want
Not saying Christmas is taking Christ out, that’s what Christmas is all about. Jesus’s birthday …… Shame shame Mr. Prez